Package pygeodesy :: Package geodesicx :: Module gxarea :: Class GeodesicAreaExact

Class GeodesicAreaExact

  object --+        
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named._Named --+    
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named._NamedBase --+
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                  GeodesicAreaExact

Known Subclasses:

PolygonArea

Area and perimeter of a geodesic polygon, an enhanced version of Karney's Python class PolygonArea using the more accurate surface area.

Note: The name of this class *Exact is a misnomer, see Karney's comments at C++ attribute GeodesicExact._c2.

Instance Methods

__init__(self, geodesic, polyline=False, name='')
New GeodesicAreaExact instance.

AddEdge(self, azi, s)
Add another polygon edge.

AddPoint(self, lat, lon)
Add another polygon point.

Compute(self, reverse=False, sign=True)
Compute the accumulated perimeter and area.

Reset(self)
Reset this polygon to empty.

Clear(self)
Reset this polygon to empty.

TestEdge(self, azi, s, reverse=False, sign=True)
Compute the properties for a tentative, additional edge

TestPoint(self, lat, lon, reverse=False, sign=True)
Compute the properties for a tentative, additional vertex

toStr(self, prec=6, sep=', ', **unused)
Return this GeodesicExactArea as string.

Inherited from named._NamedBase: __repr__, __str__, others, toRepr

Inherited from named._Named: __imatmul__, __matmul__, __rmatmul__, attrs, classof, copy, dup, methodname, rename, toStr2

Inherited from object: __delattr__, __format__, __getattribute__, __hash__, __new__, __reduce__, __reduce_ex__, __setattr__, __sizeof__, __subclasshook__

Properties
	area0x Get the ellipsoid's surface area (`meter` squared), more accurate for very oblate ellipsoids.
	area0 Get the ellipsoid's surface area (`meter` squared), more accurate for very oblate ellipsoids.
	ellipsoid Get this area's ellipsoid (`Ellipsoid[2]`).
	geodesic Get this area's geodesic object (`Geodesic[Exact]`).
	earth Get this area's geodesic object (`Geodesic[Exact]`).
	lat0 Get the first point's latitude (`degrees`).
	lat1 Get the most recent point's latitude (`degrees`).
	lon0 Get the first point's longitude (`degrees`).
	lon1 Get the most recent point's longitude (`degrees`).
	num Get the current number of points (`int`).
	polyline Is this perimeter only (`bool`), area NAN?
	verbose Get the `verbose` option (`bool`).
Inherited from `named._Named`: `classname`, `classnaming`, `iteration`, `name`, `named`, `named2`, `named3`, `named4`, `sizeof` Inherited from `object`: `__class__`

Method Details

init (self, geodesic, polyline=False, name='')
(Constructor)

New GeodesicAreaExact instance.

Arguments:

geodesic - A geodesic (GeodesicExact, wrapped Geodesic or GeodesicSolve).
polyline - If True, compute the perimeter only, otherwise area and perimeter (bool).
name - Optional name (str).

Raises:

GeodesicError - Invalid geodesic.

Overrides: object.__init__

AddEdge (self, azi, s)

Add another polygon edge.

Arguments:

azi - Azimuth at the current point (compass degrees360).
s - Length of the edge (meter).

AddPoint (self, lat, lon)

Add another polygon point.

Arguments:

lat - Latitude of the point (degrees).
lon - Longitude of the point (degrees).

Compute (self, reverse=False, sign=True)

Compute the accumulated perimeter and area.

Arguments:

reverse - If True, clockwise traversal counts as a positive area instead of counter-clockwise (bool).
sign - If True, return a signed result for the area if the polygon is traversed in the "wrong" direction instead of returning the area for the rest of the earth.

Returns:

Area3Tuple(number, perimeter, area) with the number of points, the perimeter in meter and the area in meter**2. The perimeter includes the length of a final edge, connecting the current to the initial point, if this polygon was initialized with polyline=False. For perimeter only, i.e. polyline=True, area is NAN.

Notes:

Arbitrarily complex polygons are allowed. In the case of self-intersecting polygons, the area is accumulated "algebraically". E.g., the areas of the 2 loops in a figure-8 polygon will partially cancel.
More points and edges can be added after this call.

TestEdge (self, azi, s, reverse=False, sign=True)

Compute the properties for a tentative, additional edge

Arguments:

azi - Azimuth at the current the point (compass degrees).
s - Length of the edge (meter).
reverse - If True, clockwise traversal counts as a positive area instead of counter-clockwise (bool).
sign - If True, return a signed result for the area if the polygon is traversed in the "wrong" direction instead of returning the area for the rest of the earth.

Returns:

Area3Tuple

(number, perimeter, 
          area)

Raises:

GeodesicError - No points.

TestPoint (self, lat, lon, reverse=False, sign=True)

Compute the properties for a tentative, additional vertex

Arguments:

lat - Latitude of the point (degrees).
lon - Longitude of the point (degrees).
reverse - If True, clockwise traversal counts as a positive area instead of counter-clockwise (bool).
sign - If True, return a signed result for the area if the polygon is traversed in the "wrong" direction instead of returning the area for the rest of the earth.

Returns:

Area3Tuple

(number, perimeter, 
          area)

toStr (self, prec=6, sep=', ', **unused)

Return this GeodesicExactArea as string.

Arguments:

prec - The float precision, number of decimal digits (0..9). Trailing zero decimals are stripped for prec values of 1 and above, but kept for negative prec values.
sep - Separator to join (str).

Returns:

Area items (str).

Overrides: named._Named.toStr

Property Details

area0x

Get the ellipsoid's surface area (meter squared), more accurate for very oblate ellipsoids.

Get method:: area0x(self) - Get the ellipsoid's surface area (meter squared), more accurate for very oblate ellipsoids.
Set method:: _fset_error(inst, val) - Throws an AttributeError, always.
Delete Method:: _fdel(inst) - Zap the cached/memoized property value.

area0

Get the ellipsoid's surface area (meter squared), more accurate for very oblate ellipsoids.

Get method:: area0x(self) - Get the ellipsoid's surface area (meter squared), more accurate for very oblate ellipsoids.
Set method:: _fset_error(inst, val) - Throws an AttributeError, always.
Delete Method:: _fdel(inst) - Zap the cached/memoized property value.

ellipsoid

Get this area's ellipsoid (Ellipsoid[2]).

Get method:: ellipsoid(self) - Get this area's ellipsoid (Ellipsoid[2]).
Set method:: _fset_error(inst, val) - Throws an AttributeError, always.
Delete Method:: _fdel(inst) - Zap the cached/memoized property value.

geodesic

Get this area's geodesic object (Geodesic[Exact]).

Get method:: geodesic(self) - Get this area's geodesic object (Geodesic[Exact]).
Set method:: _fset_error(inst, val) - Throws an AttributeError, always.
Delete Method:: _fdel(inst) - Zap the cached/memoized property value.

earth

Get this area's geodesic object (Geodesic[Exact]).

Get method:: geodesic(self) - Get this area's geodesic object (Geodesic[Exact]).
Set method:: _fset_error(inst, val) - Throws an AttributeError, always.
Delete Method:: _fdel(inst) - Zap the cached/memoized property value.

lat0

Get the first point's latitude (degrees).

Get method:: lat0(self) - Get the first point's latitude (degrees).
Set method:: _fset_error(inst, val) - Throws an AttributeError, always.
Delete Method:: _fdel(inst) - Zap the cached/memoized property value.

lat1

Get the most recent point's latitude (degrees).

Get method:: lat1(self) - Get the most recent point's latitude (degrees).
Set method:: _fset_error(inst, val) - Throws an AttributeError, always.
Delete Method:: _fdel(inst) - Zap the cached/memoized property value.

lon0

Get the first point's longitude (degrees).

Get method:: lon0(self) - Get the first point's longitude (degrees).
Set method:: _fset_error(inst, val) - Throws an AttributeError, always.
Delete Method:: _fdel(inst) - Zap the cached/memoized property value.

lon1

Get the most recent point's longitude (degrees).

Get method:: lon1(self) - Get the most recent point's longitude (degrees).
Set method:: _fset_error(inst, val) - Throws an AttributeError, always.
Delete Method:: _fdel(inst) - Zap the cached/memoized property value.

num

Get the current number of points (int).

Get method:: num(self) - Get the current number of points (int).
Set method:: _fset_error(inst, val) - Throws an AttributeError, always.
Delete Method:: _fdel(inst) - Zap the cached/memoized property value.

polyline

Is this perimeter only (bool), area NAN?

Get method:: polyline(self) - Is this perimeter only (bool), area NAN?
Set method:: _fset_error(inst, val) - Throws an AttributeError, always.
Delete Method:: _fdel(inst) - Zap the cached/memoized property value.

verbose

Get the verbose option (bool).

Get method:: verbose(self) - Get the verbose option (bool).
Set method:: verbose(self, verbose) - Set the verbose option (bool) to print a message after each method invokation.
Delete Method:: _fdel(inst) - Zap the cached/memoized property value.

Class GeodesicAreaExact

__init__ (self, geodesic, polyline=False, name='') (Constructor)

AddEdge (self, azi, s)

AddPoint (self, lat, lon)

Compute (self, reverse=False, sign=True)

TestEdge (self, azi, s, reverse=False, sign=True)

TestPoint (self, lat, lon, reverse=False, sign=True)

toStr (self, prec=6, sep=', ', **unused)

area0x

area0

ellipsoid

geodesic

earth

lat0

lat1

lon0

lon1

num

polyline

verbose

init (self, geodesic, polyline=False, name='')
(Constructor)